1. Field of the Invention
The present invention relates to digital portable cordless telephones and, more particularly, to apparatus and methods for managing billing information in a digital portable cordless telephone.
2. Description of the Related Art
In the case that a call service (e.g., the last incoming or outgoing call) is performed using a digital portable cordless telephone, billing information for the call service is calculated from the moment in time when the call service is completed. The calculated billing information is stored in a non-volatile memory such as an Electrically Erasable and Programmable Read Only Memory (EEPROM). In such a manner, the accumulated charge for call services from a certain point in time (e.g., the point in time when the charge details for previously performed call services have been deleted) is stored. For example, in the case of a Global System for Mobile communications (GSM), the accumulated charge for call services is stored in a non-volatile memory which is internally disposed in a subscriber identity module. Often, subscribers want to know billing information details such as, for example, the service time and the telephone number of the calling (i.e., incoming call) or called (i.e., outgoing call) party for each call service. However, conventional mobile terminals do not manage such billing information by themselves. Accordingly, if a subscriber wants to know billing information details, he or she should request such information from the service company. However, such a request inconveniences the subscriber.
It is an object of the present invention to provide apparatus and methods for managing billing information for call services performed in a digital portable cordless telephone. In accordance with the present invention, billing information details may be immediately provided to a subscriber via the digital portable cordless telephone for specific call services or for an accumulated service charge encompassing multiple call services.
In accordance with one aspect, an apparatus for managing billing information in a digital portable cordless telephone comprises: a non-volatile memory for storing the billing information, the billing information including a service charge for a specific call service and other billing information details for the specific call service; a completion sensing unit for sensing whether the specific call service is completed; a calculating unit for calculating the service charge for the specific call service; an address generating unit for generating an address at which the service charge is stored, and addresses at which the other billing information details are stored, the address of the service charge for the specific call service being linked to the addresses of the other billing information details for the specific call service; and a display unit for displaying the billing information stored in the non-volatile memory in response to a billing information display request by a user.
In accordance with another aspect, a method for managing billing information of call services in a digital portable cordless telephone having a non-volatile memory comprises the steps of: calculating a service charge for a call service when a completion of the call service is sensed; and storing the calculated service charge in a memory location of the non-volatile memory corresponding to a specified address. The method may further comprise the steps of: searching for an address of the non-volatile memory linked to the specified address at which the calculated service charge is stored; and storing a telephone number associated with the call service in a memory location of the non-volatile memory corresponding to the searched address.